Support mTLS for client authentication

[mbfm]

It should be possible to host our backend on a server with mutual authentication as second-factor for authenticating a client (2FA).

Tasks:

• [ ] Configure Traefik in Localenv with mTLS enabled https://doc.traefik.io/traefik/https/tls/#client-authentication-mtls
  • [x] Depends on: #380
  • [ ] Allow manual creation of client certificates via script in Localenv
  • [ ] Perform test deployment of Localenv
  • [ ] Test with client certificates from other CA
• [ ] Load mTLS certificate in EDGAR
  • [ ] Check OpenTelemetry client works (backend should be covered by Traefik)
• [ ] Load mTLS certificate in CLEO
• [ ] Load mTLS certificate in NetBird client NetBird likely supports mTLS in more recent versions: https://github.com/netbirdio/netbird/pull/2188
  • [ ] Depends on: #378
• [ ] Check LEA works (should only need certificate installed in browser)
• [ ] Check Grafana works (should only need certificate installed in browser)